1. Field of the Invention
This invention relates to grouting/caulking processes. More particularly, this invention relates methods and apparatus for extending the life of and restoring the water resistance to aging slate, fibrous cement or clay tile roofs.
2. Description of Prior Art
Slate tiles have been used as roofing materials for hundreds of years. Slate roofs, if properly maintained, can last for sixty to one hundred twenty five or more years; keeping the integrity of the buildings on which they are used intact and adding to the building's value.
The slate roofing industry reached its zenith in both quantity and value of output from 1897 to 1914. Consequently, many of the prominent structures constructed during that time have slate roofs that are nearing the end of their serviceable lives.
The durability of these roofs depends on many factors, one of which is the physical and mineralogical properties of slate. The natural weathering of roofing slate is a slow process of chipping and scaling of the slate along its cleavage planes. Paper-thin laminations flake off the slate surface, and the surface becomes soft and spongy as the inner layers begin to come apart, or delaminate. This process is often accelerated by the phenomena of reverse condensation in which moisture condenses on the bottom sides of the roofing slates and aids in the deterioration of the undersides of the roofing slates and the fasteners or nails that hold the slates in place.
As this weathering process continues, there is a decrease in both the strength and toughness of the slate tiles. Unless something is done to stop or decrease this weathering process, a number of the tiles that comprise a slate roof are likely to eventually break or fall out of place.
The most viable, current repair method for slate roofs is to simply replace the roof's deteriorated or broken tiles. However, there are numerous potential problems with such repairs. These include: (a) the impracticality of such repairs when there are numerous damaged tiles in a roof, (b) the possibility that even the most experienced roofing installers will damage other tiles while attempting such repairs, and (c) the frequent impossibility of replacing the damaged tiles with tiles of the same color or hue; thereby resulting in a “patchwork” of miscolored tiles that detracts from the roof's overall aesthetic appearance.
Other repair methods present even greater problems. The slate roofing industry does not consider the application of bituminous mastics or other non-permeable materials to be viable repair alternatives. These materials, though effective at first, will eventually harden and crack, allowing water to enter the tiles. The trapped moisture that results in these situations will worsen the effects of the natural freeze/thaw cycles. Also, the application of mastic materials to slate roofs makes future repairs more difficult to execute.
Thus, there exists a continuing need for the development of new and improved repair and preservation methods for slate roofs. Such methods should preferably be relatively easy to implement, and not too labor intensive or require the use of costly materials so that such repairs can be made in a cost-effective and timely manner.